When the pilot departed from Lindsay, the sky was clear, but he was aware that he would be encountering low cloud and reduced visibility in the Kitchener area, as well as possible thunderstorms in the vicinity of Manitoulin Island. En route to Kitchener, the pilot encountered weather that was worse than forecast. The constant, seemingly controlled descent from 4,500 feet until very near the ground indicates that the aircraft was under the control of the pilot. This controlled descent, in conjunction with the low ceilings and visibility reported and forecast, would indicate that the pilot was descending with the intention of maintaining visual contact with the ground or, more probably, breaking out of the cloud. Unfortunately, the pilot descended in an area of rising terrain and, prior to establishing adequate visual contact with the terrain, struck the trees and ground. As the pilot descended, he did contact the Kitchener/Waterloo control tower and was given SVFR to enter the control zone. As it turned out, the weather conditions at the Kitchener/Waterloo airport, although not suitable for VFR, were considerably better than the weather conditions that the pilot encountered en route and during his descent. It was likely that the pilot assumed the weather conditions he was operating in were similar to the reported weather conditions at Kitchener, and that by descending he would be able to maintain or regain visual contact with the ground. The aircraft had been fitted with a shoulder harness modification to the existing lap belts, but the pilot was not wearing the shoulder harness when the aircraft struck the trees; this may have been related to the inconvenience of the fixed type installation. The use of the shoulder harness likely would have reduced the severity of the upper torso injuries to the pilot. The following Engineering Branch report was completed: LP 111/95 - Instrument Examination.Analysis When the pilot departed from Lindsay, the sky was clear, but he was aware that he would be encountering low cloud and reduced visibility in the Kitchener area, as well as possible thunderstorms in the vicinity of Manitoulin Island. En route to Kitchener, the pilot encountered weather that was worse than forecast. The constant, seemingly controlled descent from 4,500 feet until very near the ground indicates that the aircraft was under the control of the pilot. This controlled descent, in conjunction with the low ceilings and visibility reported and forecast, would indicate that the pilot was descending with the intention of maintaining visual contact with the ground or, more probably, breaking out of the cloud. Unfortunately, the pilot descended in an area of rising terrain and, prior to establishing adequate visual contact with the terrain, struck the trees and ground. As the pilot descended, he did contact the Kitchener/Waterloo control tower and was given SVFR to enter the control zone. As it turned out, the weather conditions at the Kitchener/Waterloo airport, although not suitable for VFR, were considerably better than the weather conditions that the pilot encountered en route and during his descent. It was likely that the pilot assumed the weather conditions he was operating in were similar to the reported weather conditions at Kitchener, and that by descending he would be able to maintain or regain visual contact with the ground. The aircraft had been fitted with a shoulder harness modification to the existing lap belts, but the pilot was not wearing the shoulder harness when the aircraft struck the trees; this may have been related to the inconvenience of the fixed type installation. The use of the shoulder harness likely would have reduced the severity of the upper torso injuries to the pilot. The following Engineering Branch report was completed: LP 111/95 - Instrument Examination. The pilot, in an attempt to maintain or regain visual contact with the ground, descended in low cloud and heavy fog into rising terrain, and the aircraft struck the ground. The aircraft was serviceable, although the pilot shoulder harness installation was not certified. The pilot was not wearing the available shoulder harness. The pilot did not fully disclose his medical condition on his aviation medical assessments.Findings The pilot, in an attempt to maintain or regain visual contact with the ground, descended in low cloud and heavy fog into rising terrain, and the aircraft struck the ground. The aircraft was serviceable, although the pilot shoulder harness installation was not certified. The pilot was not wearing the available shoulder harness. The pilot did not fully disclose his medical condition on his aviation medical assessments. The pilot encountered weather conditions that were worse than forecast, and, in an attempt to maintain or regain visual contact with the ground in an area of low cloud and dense ground fog, he descended and the aircraft struck the ground. Contributing to the pilot's decision to continue the flight into known adverse weather conditions may have been his lack of currency, the waiting passenger, and the better weather conditions reported at Kitchener.Causes and Contributing Factors The pilot encountered weather conditions that were worse than forecast, and, in an attempt to maintain or regain visual contact with the ground in an area of low cloud and dense ground fog, he descended and the aircraft struck the ground. Contributing to the pilot's decision to continue the flight into known adverse weather conditions may have been his lack of currency, the waiting passenger, and the better weather conditions reported at Kitchener.